It's possible current expressions using makeDesktopItem will fail to build because of this change.

I don't have a beefy enough machine but I don't think it would break too much stuff.

We could modify the makeDesktopItem() using desktop-file-edit , ie in soulseekqt derivation:

desktop-file-edit \
--set-key Exec --set-value $binary \
--set-key Comment --set-value "${meta.description}" \
--set-key Categories --set-value Network default.desktop 

that way, according to documentation, you won't need to rerun validation.
and a most-wanted , and desktop-file-validate doesn't provides that, is to check if Exec value is valid.
(as in #75819 or #45347). On Arch for example, they use https://github.com/AndyCrowd/fbrokendesktop/blob/master/fbrokendesktop . It would avoid also #68035 if the validation/patching was systematic.

you can also enforce mode with --mode , avoid some desktop files like firefox ,0ad or xterm one to be executable ...

We can unify how desktop files are handles in nixpkgs, desktop-file-utils is often used in nativeBuildInputs of gnome application.

An other case in usage of desktop file directly in nixpkgs, for example openra :

    substitute ${./openra-mod.desktop} $(mkdirp $out/share/applications)/${pname}.desktop \
      --subst-var-by name ${escapeShellArg mod.name} \
      --subst-var-by title ${escapeShellArg mod.title} \
      --subst-var-by description ${escapeShellArg mod.description}

This use the same idea as in soulseekqt, fill the blank with meta properties. This could be an automatic feature with a proper .desktop.in extention.

cc @tilpner : we could offer such desktop mecanism as soulseekqt in appimageTools since all users of desktop software appimage need it and use often ugly method to fix that issue.

@bignaux Sounds good, will try this.

@bignaux I don't use .desktop files, so I'm unfamiliar with the ways used to generate them, but I'll try to review a PR to appimageTools if you send one. :)

Using this issue as a TODO, i notice we need a unified method to make the icon directories, lot use
such thing, an integrated helper would be welcome :
https://github.com/NixOS/nixpkgs/blob/de0af4a171280f085c6181b7477cefb46cc1ae83/pkgs/applications/networking/p2p/soulseekqt/default.nix#L56-L59

Edit: i forget to say i search for tools to do it well/better, i don't find any, but xdg-desktop-icon was very useless and make nothing interesting imho.

Merged because I don't think I'll have the time to improve this more.

This also broke the build of joplin-desktop. I barely know anything about desktop files, so I'm unsure how to fix this.

Fixed in 7df8136.

This broke calibre: #84095

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